Survival Motor Neuron (SMN) function in motoneuron development

运动神经元存活 (SMN) 在运动神经元发育中的功能

基本信息

批准号：
9899326
负责人：
Sharon L Amacher
金额：
$ 36.49万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-04-01 至 2022-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9899326
关键词：
Adult Affect Amyotrophic Lateral Sclerosis Axon Binding Proteins Biochemistry Biology Cells Cessation of life Child Childhood Complement Complex Data Data Set Defect Dendrites Development Diagnosis Disease Failure Functional disorder Genetic Genetic Diseases Growth Human Immunoprecipitation Infant Inherited Lead Methods Modeling Molecular Motor Motor Neurons Mutate Mutation Nature Neurons Neuropathy Neurosciences Paralysed Phenotype Positioning Attribute Problem Solving Process Proteins RNA RNA Processing RNA Transport RNA metabolism RNA-Binding Proteins Research Role SMN protein (spinal muscular atrophy)Skeletal Muscle Spectrophotometry Spinal Diseases Spinal Muscular Atrophy Testing Therapeutic Tissues Transgenic Organisms Western Blotting Zebrafish cell type design experience experimental study imaging genetics in vivo infant death innovation insight link protein motor neuron function mutant nerve supply novel novel strategies polarized cell protein complex synaptogenesis targeted treatment trafficking transcriptome sequencing

项目摘要

Project Summary Understanding the mechanistic basis of motoneuron dysfunction and its role in motoneuron diseases would fill a major gap in neuroscience and advance new approaches for treating devastating diseases such as amyotrophic lateral sclerosis (ALS), hereditary motor neuropathy and spinal muscular atrophy (SMA). These diseases afflict over one hundred thousand adults, infants, and children per year in the US. ALS and SMA are particularly devastating diseases resulting in paralysis and death often within a few years of diagnosis. The genetics of these diseases indicates that motoneurons are particularly vulnerable to defects in proteins tasked with critical RNA processing functions. However, exactly why motoneurons are vulnerable to RNA processing defects is not understood. The scientific rationale for this project is to elucidate mechanistically how mishanding of RNAs can disrupt motoneuron function and lead to motoneuron death. Elucidating the motoneuron-specific RNA processing defects caused by these mutations is essential for understanding motoneurons in both normal and diseased conditions and will direct critically needed therapeutics. To tackle this issue, we focus on the ubiquitously expressed survival motor neuron (SMN) protein and the motoneuron disease SMA. SMA is a motoneuron disease that affects infants/children and is caused by low survival motor neuron (SMN) protein levels. SMN functions in many aspects of RNA metabolism. However, the critical RNA handling function of SMN in motoneurons is unresolved. Evidence supports that SMN interacts with various neuronal RNA binding proteins (RBPs) that stabilize and/or transport RNAs to axons and dendrites during development. Using unique zebrafish models that we have generated, we have shown that SMN is required for normal vertebrate motoneuron development including dendrite formation and motor axon outgrowth and arborization. This is a key finding and reveals that SMA is not a degenerative defect, but the motoneuron dysfunction is caused by poor motoneuron development leading to neuronal failure. We hypothesize that SMN associates with neuronal RBPs and their cargo RNAs in a developmentally regulated manner to direct motoneuron development including axon out growth and branching, dendrite formation, and synapse formation. To test this we will answer three essential questions: What SMN:RBP complexes are in developing motoneurons? How do defects in these RBPs affect motoneuron development? What RNAs are in these complexes, and how are they affected when SMN or the RBPs are missing or decreased? All of our experiments will be performed in vivo in motoneurons, the relevant cell type and use a broad range of experimental approaches such as biochemistry, mass spectrophotometry, RNAseq, single neuron imaging and genetics. Data from these experiments will have broad implications for understanding RNA involvement in normal motoneuron development, SMA, and other motoneuron diseases such as ALS. In addition, our approach will rigorously test the importance of SMN:RBP complexes and their associated RNAs revealing a fundamental molecular mechanism in motoneuron biology.

项目概要了解运动神经元功能障碍的机制基础及其在运动神经元疾病中的作用将填补神经科学领域的重大差距，并提出治疗肌萎缩等破坏性疾病的新方法侧索硬化症（ALS）、遗传性运动神经病和脊髓性肌萎缩症（SMA）。这些疾病困扰着美国每年有超过十万名成人、婴儿和儿童。 ALS 和 SMA 特别是毁灭性的疾病往往在诊断后几年内就会导致瘫痪和死亡。这些基因的遗传疾病表明运动神经元特别容易受到负责关键 RNA 的蛋白质缺陷的影响处理功能。然而，运动神经元为何容易受到 RNA 加工缺陷的影响尚不明确。明白了。该项目的科学原理是从机械上阐明如何处理不当 RNA 可以破坏运动神经元功能并导致运动神经元死亡。阐明运动神经元特异性这些突变引起的 RNA 加工缺陷对于理解正常和正常运动神经元至关重要。和疾病状况，并将指导急需的治疗方法。为了解决这个问题，我们重点关注普遍表达的运动神经元存活 (SMN) 蛋白和运动神经元疾病 SMA。 SMA 是一种影响婴儿/儿童的运动神经元疾病，由低存活运动神经元 (SMN) 蛋白水平引起。 SMN 在 RNA 代谢的许多方面发挥作用。然而，SMN 的关键 RNA 处理功能运动神经元尚未解决。有证据支持 SMN 与各种神经元 RNA 结合蛋白相互作用 (RBP) 在发育过程中稳定 RNA 和/或将 RNA 转运至轴突和树突。使用独特的斑马鱼我们生成的模型表明，正常脊椎动物运动神经元需要 SMN 发育包括树突形成和运动轴突生长和分枝。这是一个关键发现揭示SMA并非退行性缺陷，而是运动神经元功能不良导致运动神经元功能障碍发育导致神经元衰竭。我们假设 SMN 与神经元 RBP 及其相关货物RNA以发育调节的方式指导运动神经元发育，包括轴突生长和分支、树突形成和突触形成。为了测试这一点，我们将回答三个基本问题：什么 SMN:RBP 复合物在发育中的运动神经元中起作用？这些 RBP 中的缺陷是如何产生的影响运动神经元发育？这些复合物中有哪些 RNA，以及当 SMN 或 RBP 缺失或减少？我们所有的实验都将在运动神经元体内进行，相关的细胞类型并使用广泛的实验方法，如生物化学、质谱、 RNAseq、单神经元成像和遗传学。这些实验的数据将产生广泛的影响了解 RNA 参与正常运动神经元发育、SMA 和其他运动神经元疾病，例如作为肌萎缩侧索硬化症。此外，我们的方法将严格测试 SMN:RBP 复合物及其相关的重要性 RNA 揭示了运动神经元生物学的基本分子机制。